Viruses
behave in different ways. Some viruses stay active in memory until
you turn off your computer. Other viruses stay active only as long
as the infected applications is running. Turning off your computer
or exiting the application removes the virus from memory, but does
not remove the virus from the infected file or disk.
Some
viruses are programmed specifically to damage the data on your computer
by corrupting programs, deleting files, or erasing your entire hard
disk.
All
computer viruses are manmade. A simple virus that can make a copy
of itself over and over again is relatively easy to produce. Even
such a simple virus is dangerous because it will quickly use all
available memory and bring the system to a halt.
Trojan
horses are not viruses; however, they are often thought of as viruses.
A trojan horse is a program that appears to serve some useful purpose
or provide entertainment, which encourages you to run it. But, like
the Trojan horse of old, it also serves a covert purpose which may
be to damage files or perhaps plant a virus on your computer.
Many
computer viruses turn out to be hoaxes or myths. Hoaxes are false
alerts about viruses that don't exist. Check out Snopes Urban Legends for more info on hoaxes. For another list of hoaxes check
out F-Secure Hoaxes. Another good site to visit is Computer Virus Myths. And of
course at the Symantec site (Norton) this is their Hoax
Info page.
I
highly recommend that you have Virus Protection installed in your
computer before you consider downloading anything.
